#include"Date.h"
Date& Date:: operator+=(int day)
{
	if (day < 0)
	{
		return *this -= -day;
	}
	_day += day;
	while (_day > GetMonthDay(_year, _month))
	{
		_day -= GetMonthDay(_year, _month);
		_month++;
		if (_month > 12)
		{
			_year++;
			_month = 1;
		}
		
	}
	return *this;
}
Date& Date::operator-=(int day)
{
	if (day < 0)
	{
		return *this += -day;
	}
	_day -= day;
	while (_day <= 0)
	{
		_month--;
		if (_month < 1)
		{
			_year--;
			_month = 12;
		}
		_day += GetMonthDay(_year, _month);
	}
	return *this;
}
Date Date::operator-(int day) const
{
	Date tmp = *this;
	tmp -= day;
	return tmp;
}
Date Date::operator+(int day) const
{
	Date tmp = *this;
	tmp += day;
	return tmp;
}
bool Date::operator<(const Date& d) const
{
	if (_year < d._year)
	{
		return true;
	}
	else if (_year == d._year && _month < d._month)
	{
		return true;
	}
	else if (_year == d._year && _month == d._month && _day < d._day)
	{
		return true;
	}
	return false;
}
bool Date::operator==(const Date& d) const
{
	return _year == d._year && _month == d._month && _day == d._day;
}
bool Date::operator!=(const Date& d) const
{
	return !(*this == d);
}
int Date::operator-(const Date& d) const
{
	int flag = 1;
	Date min = *this;
	Date max = d;
	if (max < min)
	{
		min = d;
		max = *this;
		flag = -1;
	}
	int day = 0;
	while (min != max)
	{
		min += 1;
		day++;
	}
	return flag * day;
}